Pattern-drawing apparatus.



H. P. MACDONALD. PATTERN DRAWING APPARATUS.

APPLIOATION FILED 2080.26, 1912.

Patented Feb. 24, 1914,

/ 3 SHEETS-EHEIM 1.

. H. P. MACDONALD.

PATTERN DRAWING APPARATUS.

APPLIOATION FILED 1320.26, 191A. I

Patented Feb. 24, 1914.

1,088,083. 4 i 3 SHEETS-SHEET 2.

WI TN ESSES I I/ EN TOR. 7; :4, ,M/ 4 y #M 8 BY TORNEY.

H. P. MACDONALD. I PATTERN DRAWING APPARATUS.

APPLIGATION FILED DB0. 2e, 1912.

- Patented Feb. 24, 1914 3 SHEETS--BHEBT 3.

COLUMBIA PLANbGRAPH Co.. WAsHxNaToN. D. C,

the cut-out switch, taken on the line of UNITED STATES` PATENT OFFICE.

HARRY I?. lfIACDONALD, OF IVIONTCLAIR, NEW JERSEY, ASSIGNOR TO THESNEAID & CO. IRON VVORKS, OF JERSEY CITY, NEW JERSEY, A CORPORATION OFNEW JERSEY. v

PATTERN-DRAWING APPARATUS.

K Specilicaton of Letters Patent.

Application filed December 26, 1912.

Patented Feb. 24;, 1914. Serial No. 738,694.

To all whom t may concern Be it known that I, HARRY P. MACDONALD, acitizen of the United States, residing at Montclair, in the county ofEssex and State of New Jersey, have invented certain new and usefulImprovements in Pattern-Drawing Apparatus, of which the following is aspecification.

This invention relates to pattern drawing apparatus and it has for itsprimary ob- `jects; the provision in apparatus of the characterdescribed of improved operating mechanism; the provision of an improvedarrangement of actuating and adjusting mechanism; the provision ofimproved means for maintaining an approximately constant load pressureon the operating mechanism; and the provision of an improved means forguiding the apparatus in the drawing operations.

My invention further contemplates the driving of the apparatus by meansof a motor and the provision of improved rapper mechanism actuated bysaid motor. A further object resides in the provision of improved meansfor controlling the motor. These, together with such other objects asmay hereinafter appear, or are incident to my invention, I obtain bymeans of a construction which I have illustrated in preferred form inthe accompanying drawings, wherein- Figure 1 is a plan view ofapproximately half of the drawing apparatus with the pattern supportingtable or plate'broken away to illustrate the operating mechanism; Figure2 is an irregular, longitudinal section of the device taken on the lineII-II of Figure 1; Figure 3 is a diagrammatic view of the entireapparatus and indicates the operative positions of the actuatingmechanism; Figure 4 is a sectional view, drawn on a larger scale,illustrating the rapper mechanism; Figure 5 is an end view of the rappermechanism; Figure 6 is a section taken on the line VI-VI of Figure 4;Figure 7 is a longitudinal section through the clutch mechanism, betweenthe motor and the operating mechanism; Figure 8 illustrates the electricwiring, the control switch and automatic cut-out switch; and Figure 9isa section through one of the contact blocksof Fleur@ S @ne of theprimary purposes for which l my invention is designed is the provisionof a pattern drawing mechanism, adapted for use in drawing patterns ofgreat length. Referring to Figures 1, 2 and 3 particularly, it will beseen that I have provided a main frame 7 which contains the operatingmechanism and the pattern supporting plate or table 8, the frame beingclosed at the bottom by means of the plate 9. The pattern table 8 closesthe top of the frame, and the ends of the frame are closed by means ofplates 10.

The particular form of drawing apparatus illustrated is designed for usein connection with roll ramming apparatus, and to this end I haveprovided a frame 7 with upstanding ledges l1 which serve to close thesides of the frame and also support the flask, which is filled with sandand rammed byl a rammingroll in the'usual manner.

From the foregoing it will be readily apparent that when the parts areassembled the frame provides a practically inclosed chamber in which theoperating mechanism is contained. The advantage of this construction isthat sand and other foreign matter which would be injurious to theoperating mechanism is eectively excluded,

As previously stated, this device is particularly applicable for makingmolds for long flat castings, and it is desirable to support the patterntable at a plurality of points on the operating mechanism. Brieflydescribed, the operating 'mechanism comprises a vertical threaded shaft12, such shaft being mounted in a saddle frame 13 in the central portionof the apparatus. Ball thrust bearings 14 are provided at the ends ofthe shaft. The shaft carries a block or nut 15, which in turn isconnected to a pair of rock arms 16 and 17, keyed to the rock shafts 18and 19, by means of the links 20 and 21, the rock shafts 18 and 19 beingmounted in bearings in the saddle frame 18. Each rock shaft has keyed toit two rock arms 22 and 22, said arms being connected to a pair oftoggles 23 and 23 by means of the connecting rods or links 24 and 25.The toggles 23 and 23 are located substantially half way between thevertical operating sha-ft 12 and the endsofA the frame 7. Lo-

l side of the pattern support and are adaptedby means of links 27. Thearrangement of prevent any longitudinal or lateral displacetogglemembers and operative connections is clearly shown in Figure 3.

- The upper lever of each of the toggle members is pivotally connectedto the pattern table by means of the adjustable spindles 28 whichproject through bosses 29 formed on the bottom of the pattern support,and are secured by means of the nuts 30, the partsbeing so arranged thatthe nuts 80 are below, or at the most substantially ,flush with theupper surface ofthe pattern support. The lower lever of each togglemember is pivotally secured to the blocks 31 carried by the frame. Itwill thus be seen that I have provided an S-point support for thepattern table, and that by turning the threaded spindles 28' the patternsupport may be readily adjusted. rihe provision of the 8-point supportand the arrangement of adjusting means is of peculiar advantage inapparatus of this kind in that it has been commonly found that patternsare not absolutely true, and it is frequently necessary to lower onecorner or one edge of the pattern plate leaving the others at adifferent height. It will bereadily seen that by my arrangement ofoperating mechanism any vof the corners may be varied in elevationwithout necessarily disturbing the others,

that is to say, any portion between they points of support may bewarpedwith respect to the other portions, and herein lies one of thechief advantages of the S-point support. Y y

Adjacent the ends of the pattern support I have provided pairs of guidepins 82, said guide pins being adapted to engage apertured lugs 33formed on the ends of the frame 7. In order to prevent stickingY orbinding of the guide posts, should it be necessary to vary the elevationof any one of the corners of the pattern support, VI have mounted theguide posts in the pattern support in the following manner:

Recessed bosses 34 are cast on the under to. receive the spherical ends35 of the guide posts 32. The guide posts are placed in position and thepattern table is'lowered and carefully leveled, the ends 35 of the guideposts lying within the recessed bosses 34 when the patterntable is inits lower or down position.v The recesses are then filled with Babbittmetal 36, such metal serving toA secure the guide posts in the patterntable or support while at the same time permitting of a slight movementof the guide posts when any of the corners of the pattern table areadjusted, the joint between being in effect a ball and socket joint. Bythis arrangement any of the-corners of the table may be adjusted withoutcausing the posts to bindv inthe'frame 7, while 'at the same time theconstruction is such that the guide posts ment of the pattern table.

In order to lock the pattern table and its operating mechanism inposition for the ramming operation, and in order to relieve theoperating mechanism of the load pressure of the rainining mechanismduring the ramming operation, I arrange the toggles in such manner thatthey pass center and take against the abutments 37, adjustably mountedin the block 3l. Then the toggles have passed center they engage theabutinents and the weight of the apparatus holds the parts in thisposition, and the drive shaft and the operative connections there fromto the toggles, together with the motor for driving the shaft, arerelieved from the load of the pattern table and of the rammingapparatus.

Another feature of the invention resides in the provision of meanswhereby the load pressure on the operating mechanism through the cycleof movement of the table is maintained at an approximately constantamount, thus securing evenness and continuity of the movement of thetable and reducing the liability of injury to the molds. At the sametime the motor and operative connections are relieved of undue stress. Iaccomplish this in the following manner.

The pattern support is provided with a plurality of downwardlyprojecting pins 38, which are in substantial alinement with the ends ofthe blocks 31 and with the brackets 31a of the saddle blocks 13. Theupper poi'- tions of the blocks and the brackets are recessed to receivecompression springs 39, said springs being adapted to slip over theposts 38. These compression springs do not have sufficient strength tocarry the load of the pattern table, but serve to cushion the table andassist the operating mechanism when the table is leaving or is returningto initial position, at which times the toggles act to least advantage.

I also provide a second set of springs 4:0, which are arranged in pairsat the ends of the pattern table. The springs 40 however, are tensionsprings and are secured at one end to the links 27 and at the other endto the frame 7 by means of the round headed screws 4l. The sphericalheads of the screws 4l permits the springs 4() to always stretch in astraight line. It will be apparent that when the table is in lowerposition the springs 40 exert their maximum tension on the toggles, andwhen the toggles are nearly vertical that the springs have contracted toapproximately initial size, though they still have a large leverage onthe toggles and exert considerable pull thereon because of the relationof the toggles to the table at that time. A

.y This arrangement of springs is of special advantage, as it willappear that if the ver tical springs alone areused and such springs werestrong enough to support considerable proportion of the weight of thepattern plate and pattern when the former is at its eXtreme upwardposition, then they vwould exert too much stress when the plateislowered and the toggle mechanism is actingin a more disadvantageousposition. Both the springs 39 and the springs 40 exert their greatestenergy when the toggles are least effective in both the raising and thelowering movements of the table. By the use of vertical springs inconnection with the horizontal springs acting directly on the toggles,

the pattern plate is approximately in balance in all positions and asubstantially constant load pressure is maintained on the operatingmechanism at all periods of the movement of the table.

It will be readily understood that when the shaft 12 is rotated in onedirection the nut 15 is drawn downward, and that when rotated in theother direction the nut 15 is elevated, and that these movements of thenut respectively secure the raising and the lowering of the patterntable. The shaft 12 is turned by the motor 42 by means of the followingoperative connections: A gear 43 is mounted on the upper portion of theshaft 12 and is engaged by the bevel gear 44 mounted on the end of theshaft 45, on the other' end of which is mounted a worm wheel 46 which isturned by means o-f the worm 47 carried on the shaft- 48, which isturned by the motor 42 through the clutch mechanism 49.

Referring to Figure 7 it will be seen that the clutch mechanismcomprises two members 50 and 51, the member 50 being feathered to theshaft 52 of the motor 42, while the member 51 is keyed to the shaft 48.The member 50 rotates with the shaft 52 but has slight relativelongitudinal movement with respect thereto. The end of the shaft 48projects within the member 50 and is provided with a nut 53 and a spring54, said spring being adapted to engage a bearing washer 55 carried inthe member 50, and also to engage the nut 53. A friction disk 56 islocated between the opposing faces of the members 50 and 51 and is heldin position by reason of the fact that the spring 54 thrusts the member50 toward the member 51. This arrangement of clutch mechanism causes therotation of the shafts 48 and 45 when the motor 42 is running, b ut incase the motor should continue to run after the operating parts havereached their respective operative positions, the member 50 will slip onthe friction disk 56 and prevent injury to the operating mechanism. Theten'sionof `the spring 54 can be varied by adjustingthe nut 53.

Another advantage of my invention rcgslde's inthe provislon .of amechanical 'rapping means operated directly from the motor Y whichactuates thel pattern drawing mechanism.V 'I accomplish this byproviding an arm 57 which has a bearing in the block 58 bolted to theside of the frame 7. One end of the arm 57 projects within the frame 7,

being guided in the guideway of the stirrup 61. The hammer 64 can sliderelative to the shoes inasmuch as the outer shoe is held in engagementwith the hammer by means of the spring 67 carried in the end of the arm57. While the hammer 64 will slide up and down as the arm 57 isoscillated by the eccentric 60, its movement will be retarded by thepressure of the spring 67 against the shoe 66. The hammer will rap theanvils smartly at each movement and thus secure the vibration of thepattern support and facilitate the drawing of the pattern. It will beapparent that the elevation of the pattern table will not affect theloperation of the rapper.

This arrangement of rapper mechanism is very simple while at the sametime it is positive in its action and does not stick or bind, as isfrequently the case in pneumatic vibrator constructions. Anotheradvantage of this construction resides in the fact that the weight ofthe blows delivered by the hammer 64 can be regulated by varying thetension of the spring 67 on the shoe 66. This is accomplished byadjusting the threaded block 68 in the end of the arm 57. Anotheradvantage of the construction is that the need of a separate controlmechanism for the vibrator' is dispensed with inasmuch as the 'hammer 64is actuated as son as the motor is started. Y

The operation of the apparatus thus far described is as follows,assuming that the parts are in the position indicated in Figure 3, infull lines: The motor is actuated and turns the shaft 12 in such manneras to cause the nut 15 to move downwardly, such movement of the nutcausing the rock shafts 16` and 19 to be rotated in the directionindicated by the arrows in Figure 2. This movement of the rock shaftsimparts an outward movement to thevrock arms 22, and causes the sets oflinksld24, 25 and 27 to straighten out the eight' toggle members, thuselevating the pattern table. y

The position of the parts when in upper pes'itcn is illustrated indotted .lilies in Fig= ure 3. When upper positionthe toggleshavetraveled slightly past center and take against the abutments 37,Ywhereby the lock- ,ing of the pattern table against downward movementissecuredand the load pressure of the table taken off the operatingshaft motor and operative connections. As soon as the. parts havereached upper position the motor is stopped and the sand in the flasko-n fmovements of the pattern table the vibrator vmechanism is beingactuated by the motor Vand securesthe effective drawing of the pat tern.After the pattern is drawn the com? pleted mold is removed in the usualmanner. As previously pointed out, during the above described movementsof the parts the springs 59 and 40 maintain an approximately constantload pressure on the anism.

Y It is desirable to' have the motor automatically stopped at the limitsof the movement of the operating mechanism, and to this end I have4pro-vided a control means consisting of a limit switch and a controlswitch. The limit switch comprises a switch Vplate 69 which is mountedon the shaft 18 and to which is pivotally `mounted ka pair of contactarms 7() and 71 which are normally held against the ends of the block 72 by means of the springs 73, one end of each of which is fastened to anarm and the other end to one of the pins 74. Secured tothe framework ofthe apparatus is a fixed plate 75, preferably formed of non-conductingmaterial, and

f which is provided with contact blocks 76 and 77, comprising a pair ofplates which are spaced apart to provide grooves 78 into which the endsof the Contact arms 70 and 71 fit.

The contact arms have a reasonably close fit in Vthe grooves, so thatwhen the switch plate 69 is rotated with the shaft 1S, either one of thearms that happens to be in contact with a contact plate will lagslightly behind until it vreaches the end of the contact plate, at whichtime a spring 7 3 will cause it to leave the groove with a snap so as toprevent electric varcing The springs 73 do not have suflicient istrength to pull the contact arms 70 and 71 through the grooves, and Ihave provided set screws 94 and 95 threaded in brackets secured to theswitch plate 69. When the switch plate. is moving in the direction ofthe arrow'the arm 71 will lag behinduntil the screw 94 abuts against itand Ycarries it along with the switch plate. By adjusting Ithe setoperating mech-l lcontact with the block 7 7 can be varied. The setscrew 95 performs the same functions for the arm 70.

The control switch 82 is of the double pole double throw type, the pivotpoints 83 and 84 of which being connected to the main feed wires 85 and86.

The parts being in the position indicated in Fig. 8, the motor isactuated to rotate the shaft 12 and raise the table by throwing theswitch to engage the contacts A and B, and the circuit is completed, thecurrent flowing from wire 85 through contact A and wire 8S to the righthand side of the armature, and thence through the wire S9, wire 90,contact arm 71, block 77, wire 91, contact B, and negative wire S6. Asthe table rises the rock shaft 1S is rotated in the direction of thearrow, until the arm 71 snaps out of the block 77 and thus breaks thecircuit. This.

versed by changing the direction of the flow,

of the current through the armature, and rotates the shaft 12 in the'reverse direction and lowers the table. The field windings are soconnected that the direction of current therethrough is independent ofthe side to which the switch is thrown, so that the reversal of theswitch merely changes the direc-tion of the current through thearmature. When the arm snaps out of the block 76 the circuit is againbroken.

It will be apparent that the control is simple, and that thc entireoperation of the device is conveniently accomplished. The limit switchand the motor and driving connections outside the main frame areinclosed in a casing or frame 7a which permits of convenient access tothe said parts, but effectively excludes sand or other foreign matter.

It will be apparent that the tension exerted on the toggle mechanism bythe springs 40 may be varied by adjusting the screws 41.

Having thus described my invention and illustrated its use, what I claimas new and desire to secure by Letters Patent is the screw the length oftime that the arm is in 1 bination of a ymovable pattern supporting 13utable, toggle members for raising and lowering the pattern table, andmeans whereby the load pressure of the table on the toggle membersduring the cycle of movement of the latter is maintained approximatelyconstant.

3. In pattern drawing apparatus, the combination of a movable patternsupporting table, toggle means for raising and lowering the patterntable, and means whereby the load pressure of the table on the togglemeans during the cycle of movement of the latter is maintainedapproximately constant, said means comprising a counter-balance meansexerting its maximum pressure on the toggle means when the latter isleast eliective, and exerting less pressure when the toggle means ismost eective.

4L. In pattern drawing apparatus, the combination of a movable patternsupporting table, toggle members for raising and lowering the patterntable, and means whereby the load pressure of the table on the togglemeans during the cycle of movement of the latter is maintainedapproximately constant, said means comprising a counter-balance springexerting its maximum pressure on the toggle means when the latter isleast effective, and less pressure on the toggle means when the latteris most ett'ective.

5. In pattern drawing apparatus, the combination of a movable patternsupporting table, toggles for raising and lowering the table, means foroperating the toggles, and counter-balance springs connected to thetoggles, exerting greatest pressure on the toggles when the toggles areleast effective, and less pressure when the toggles are most effective.

6. In pattern drawing apparatus, the combination of a frame, a movablepattern table therefor, a toggle for raising and lowering the table,means for operating the toggle, and a tension spring one end of which issecured to the frame at one end and at the other to the toggle, saidspring exerting its greatest tension when the toggle acts to leastadvantage.

7. In pattern drawing apparatus a frame, a movable pattern tabletherefor, a plurality of toggles for raising and lowering the table, acommon means for operating the toggles, and counter-balance means :tormaintaining the load pressure of the table on the operating mechanismapproximately constant during the movement of the table, said meanscomprising tension springs secured at one end to the toggles and at theother to the trame, and exerting a maximum tension when the toggles actto least advantaffe.

bS. In pattern drawing apparatus a frame, a movable pattern tabletherefor, a plurality of toggles for raising and lowering the table,means for operating the toggles,

and counter-balance means for maintaining 4the load pressure of thetable on the operating mechanism approximately constant during themovement of the table, said means comprising compression springs securedat oneend to the toggles and at the other to the frame, said springsexerting maximum pressure when the toggles act to least advantage, andless pressure when the toggles act to best advantage.

9. In molding apparatus the combination of a movable pattern supportingmember or table, a. multi-point support for said table, connectionsbetween the support and the table whereby any portion ot' the table maybe varied in elevation with respect to other portions, and guide meansfor thetable adapted to prevent lateral displacement of the table butpermitting of vertical adjustment of portions of the table with respectto other portions without binding.

10.,In molding apparatus, the combinafl tion of a movable patternsupporting member or table, a multi-point support for said table,connections between the support and the table whereby a portion of thetable can be varied in elevation with respect to other portions thereof,and swiveled guide means preventing lateral displacement of the tablebut permitting adjustment of portions of the table without binding.

1l. In molding apparatus the combination of a frame, a movable patternsupporting table therefor, a multi-point support for said table,connections between the support and the table whereby any portion of thetable can be varied in elevation with respect to other portions thereof,and a guide post having a ball and socket connection with the tableengaging the trame and preventing lateral displacement of the table. l

l2. In a molding apparatus, the combination of a movable patternsupporting member or table, a motor for raising and lowering the table,and a reciprocative rapper mechanism for vibrating the table as it ismoved by the motor and an operative connection between the motor and therap per mechanism.

13. In molding apparatus, the combination or' a movable pattern table orsupport, a rapper carried thereby and having reciprocative movement, arelatively fixed motor, and an operative connection between the motorand the rapper whereby the rapper -is actuated to vibrate the table,said operative connection having a sliding engagement with the rapper.

14. In molding apparatus, the combination of a movable pattern table orsupport, a rapper carried thereby and having reciprocative movement, arelatively fixed motor, and an operative connection between the motorand the rapper whereby the rapper tive connection having slidingfrictional engagement with the rapper.

l5. In molding apparatus, the combination of a movable pattern table o-rsupport, a reciprocatory rapper carried thereby, a relatively fixedmechanical means for imparting vertical reciprocative movement. to therapper, and a vslip connection between the actuating means and therapper whereby the rapper is actuated but is free to move with thetable.

16. In molding apparatus, the combinai tion of a support, a movablepattern table, a

motor carried on the support, a reciprocatory rapper carried by themovable table, an oscillating arm mounted on the support operated fromthe motor, and a sliding connecy tion .between the arm and rapper.

17. In molding apparatus, the combination o a support, a movable patterntable, a motor ,carried on the support, a rapper car` ried on the table,an oscillating arm pivoted to the support,'an eccentric operated by themotor for oscillatingthe arm, and a slip connection between the rapper.and the arm. y 18. In molding apparatus, lthe combination of a'support,a movable pattern table, a motor carried on the support, a stirrup onthe table, a rapper bar therefor, an oscillating arm pivoted Vto thesupport,` an eccentric operated by the motor for actuating the arm, anda 'friction connection between t-he arm .and vrapper bar.

19. In molding apparatus, the combination of a support, a movablepattern table, a motor carried on the support, a stirrup on the table, ashoe slidable in the stirrup, a rapper bar slidable in the shoe, anoscillating arm pivoted to the support, and an eccentric operated by themotor for actuating the arm, said arm engaging the shoe.

20. In molding apparatus, the combinal tion of a support, a movablepattern table, a

motor carried in the support, a stirrup carried by the table, a pair ofshoes slidable in the stirrup, a rapper bar slidably mounted between theshoes, an oscillating arm pivoted to the support and engaging the shoes,yielding means for holding the shoes in engagement with the rapper bar,an eccentric operated by the motor for actuating the arm.

21. In molding apparatus the combination of a support, a movable patterntable, a motor carried in the support, a stirrup carried by the table, apair of shoes slidable in the stirrup, aV rapper bar slidably mountedbetween the shoes, an oscillating arm pivoted to the support andengaging the shoes, spring means for holding the shoes in engagementwith the rapper bar, means for adjusting the tension of the springmeans, and an eccentric operated by the motor for Y actuating the arm.

. 22. In a molding apparatus, the combination of a support, a movablepattern table,

a motor carried on the support, a rapper, an oscillating arm mounted onthe support operated from the motor and a connection between the arm andthe rapper.

23. In molding apparatus, the combination of a movable pattern table orsupport, al reciprocatory rapper, a relatively iixed motor, and anoperative connection between the motor and the rapper whereby the rapperis actuated to vibrate the table, said operative connection having asliding engagement with the rapper.

24C. In molding apparatus the combination of a frame, a movable patterntable mounted therein, guideways in the frame, guide posts engaging theguideways having a ball and socket connection with the table, and meansfor varying the angular inclination of the table.

25. In molding apparatus the combination of a frame, a movable patterntable mounted therein, guideways in the frame, guide posts engaging theguideways having a ball and socket connection with the table, and meanswhereby a portion of the table may be flexed relative to other portionsthereof.

2G. In molding apparatus the combination of a movable pattern table,means for raising and lowering the table, a reciprocatory rapper forvibrating the table as it is moved, and a relatively xed mechanicaloperating member for the rapper, the rapper being slidably mounted onsaid member so as to accommodate itself to variations in the verticalposition of the table.

27. In molding apparatus the combination of a pattern table or support,adapted to be raised and lowered, a rapper for vibrating the table as itis being moved, and a relatively fiXed operating member for the rapper,said rapper having slidable engagement with the operating member.

28. In molding apparatus the combination of amovable pattern supportingtable, means for raising and lowering the table, the table beingsupported on said means at a plurality of points, means whereby aportion of the table between points of support can be warped, and guidemeans for guiding the table in its raising and lowering movements, saidguide means having a mounting whereby the table can be warped Withoutcausing binding of the guide means.

29. In molding apparatus the combination of a movable pattern supportingtable, means for raising and lowering the table, the table beingsupported on said means at a plurality of points, means whereby aportion of the table between points of support can be warped, and guideposts for guiding the table in its raising and lowering movements, saidguide posts having a mounting whereby the table can be warped withoutcausing binding of the guide means.

30. In molding apparatus, the combination of a movable pattern table orsupport, a to move with the table while being recip- 10 rapper bar forvibrating the table, having roeated.

vertical reoiprooative movement and mov- In testimony whereof I havehereunto able with the table, a relatively Xed mesigned by name in thepresence of the two chanical means for reciprocating the rapper,subscribed witnesses.

and an operative connection between said HARRY P. MACDONALD. means andthe rapper, the said rapper hav- Witnesses:

ing a friotional sliding engagement with J. F. ARNOLD,

said connection whereby the rapper is free C. C. GREENLEE, Jr.

Copies of this patent may be obtained for ve cents each, by addressingthe Commissioner of Patents, Washington, D. C.

